Modular headrest-based audio system

Abstract

An automobile audio system includes a signal processor configured to receive and process audio signals from a source and provide processed audio signals to an amplifier, a first headrest including a headrest speaker and coupled to a driver's seat, a first fixed speaker positioned near a left corner of the vehicle's cabin forward of the headrest, a second fixed speaker positioned near a right corner of the vehicle's cabin forward of the headrest, and a headrest accessory port located in a passenger's seat. The port is configured to connect the audio system to a second headrest speaker. The processor uses a first set of parameters for processing the received audio signals when the first headrest speaker is connected and the second headrest speaker is not connected, and a second set of parameters for processing the received audio signals when both the first and second headrest speaker are connected.

What is claimed is: 
     
       1. An automobile audio system comprising:
 a signal processor configured to receive and process audio signals from a source and provide processed audio signals to an amplifier, 
 a first headrest comprising a first headrest speaker connected to the automobile audio system and coupled to a driver's seat, 
 a first fixed speaker positioned near a left corner of the vehicle's cabin forward of the first headrest, 
 a second fixed speaker positioned near a right corner of the vehicle's cabin forward of the first headrest, and 
 a headrest accessory port located in a passenger's seat, the headrest accessory port configured to receive a connector of a second headrest speaker in a second headrest and connect the automobile audio system to the second headrest speaker when the connector is received by the headrest accessory port, 
 wherein the automobile audio system is configured to detect whether the second headrest speaker is connected to the automobile audio system, and 
 wherein the signal processor uses a first set of processing parameters for processing the received audio signals when the first headrest speaker is connected to the automobile audio system and the second headrest speaker is not detected as being connected to the automobile audio system, and 
 the signal processor uses a second set of processing parameters for processing the received audio signals when the first headrest speaker is connected to the automobile audio system and the second headrest speaker is detected as being connected to the automobile audio system. 
 
     
     
       2. The automobile audio system of  claim 1 , wherein the processed audio signals provided to the amplifier for each of the first fixed speaker and the second fixed speaker using the first set of processing parameters are different from the processed audio signals provided for the first fixed speaker and the second fixed speaker using the second set of processing parameters. 
     
     
       3. The automobile audio system of  claim 1 , wherein the processed audio signals provided to the amplifier for the first headrest speaker using the first set of processing parameters are different from the processed audio signals provided for the first headrest speaker using the second set of processing parameters. 
     
     
       4. The automobile audio system of  claim 1 , wherein the processed audio signals provided to the amplifier for the first headrest speaker using the second set of processing parameters are different from the processed audio signals provided for the second headrest speaker using the second set of processing parameters. 
     
     
       5. The automobile audio system of  claim 1 , wherein the signal processor remixes the audio signals from the source into intermediate signals corresponding to a set of component directions, and
 each of the first and second set of processing parameters distributes different portions of the intermediate signals corresponding to each of the component directions to the first headrest speaker and the first and second fixed speakers. 
 
     
     
       6. The automobile audio system of  claim 1 , wherein the automobile audio system does not include fixed speakers in the vehicle cabin located rearward of the first headrest. 
     
     
       7. The automobile audio system of  claim 1 , wherein the processed audio signals provided to the amplifier minimize leakage of sound from the driver's seat to the passenger's seat. 
     
     
       8. The automobile audio system of  claim 1 , wherein the first headrest speaker comprises at least two electroacoustic transducers, at least one located at either end of the first headrest. 
     
     
       9. The automobile audio system of  claim 8 , wherein the processed audio signals provided to the amplifier for the first headrest speaker control cross-talk of signals between each one of the at least two electroacoustic transducers and an ear of the listener positioned near a different one of the at least two electroacoustic transducers. 
     
     
       10. The automobile audio system of  claim 1 , wherein the first headrest speaker comprises a pair of arrays of electroacoustic transducers located at either end of the first headrest. 
     
     
       11. The automobile audio system of  claim 1 , wherein the first headrest speaker comprises an array of electroacoustic transducers located inside the first headrest. 
     
     
       12. The automobile audio system of  claim 1 , further comprising a bass unit accessory port configured to connect the automobile audio system to a bass unit, wherein the signal processor uses a third set of processing parameters for processing the received audio signals when a bass unit is connected to the automobile audio system. 
     
     
       13. The automobile audio system of  claim 12 , wherein the processed audio signals provided to the amplifier for each of the first fixed speaker and the second fixed speaker using the third set of processing parameters are different from the processed audio signals provided for the first fixed speaker and the second fixed speaker using either the first or the second set of processing parameters. 
     
     
       14. The automobile audio system of  claim 12 , wherein the processed audio signals provided to the amplifier for the first headrest speaker using the third set of processing parameters are different from the processed audio signals provided for the first headrest speaker using either the first or the second set of processing parameters. 
     
     
       15. The automobile audio system of  claim 1 , wherein the automobile audio system is configured to detect whether the second headrest speaker is connected by periodically polling an impedance of cabling that is coupled at one end to the headrest accessory port located in the passenger's seat.